This invention relates to mechanism for automatically maintaining a uniform release clearance (and therefore a uniform actuating stroke) for brakes and similar equipment. Mechanisms of this type are commonly used in brake systems to compensate for wear of the brake linings and other brake parts and are popularly called "automatic brake adjusters." Although the present invention is explained here in connection with brakes, the mechanism has utility in other environments where similar wear compensation is needed such as in clutches.
The basic brake adjuster designs have included mechanical adjusters with special ratchets or friction dragging parts to provide the adjustment for wear. Also hydraulic adjusters utilizing the metering of hydraulic fluid have been used.
The mechanical brake adjusters have required specially machined parts and these machined parts have been relatively costly to manufacture. This has increased the cost of servicing the adjusters when replacement has been necessary. There has also been a problem in determining when replacement of these machined parts is needed. It is highly undesirable to wait until there is failure or malfunction of the adjuster parts before replacing the parts because of the adverse affect on the braking efficiency and the unscheduled maintenance which can cause grounding of an aircraft until a repair of the adjuster is made. It has been proposed to use a ductile deformable tubular member which can be replaced each time the friction members are replaced to provide the adjustment for wear. This device requires a special construction of the adjusters because the deformation of the tubular member must be in tension as by pulling an enlarged deformed member through the tube. There also are problems removing the deforming member from the tubular member before it can be replaced. Furthermore, the ductile material must have a specified softness for satisfactory operation.